The gastrointestinal tract is home to a myriad of microbes;the intestinal microbiota (IM). This microbiota interacts with the host playing a crucial role in the maintenance of health. During adult life, in absence of external disturbance, the IM is relatively stable in absence of external disturbance, but an altered profile is often observed in elderly. However, our knowledge on the microbiota changes along ageing is still limited. In this study, we aimed at characterising the levels of selected the main intestinal microorganisms and short chain fatty acids (SCFA) along ageing. We recruited 185 adults from four age-groups; : under 50, 50-65, 66-80 and over 80 years-old (yo). Fresh faecal samples were collected for IM analyses. L levels of different bacterial groups were determined by quantitative PCR and those of SCFA by gas chromatography. Moreover, dietary habits information was collected by using a validated Food Frequency Questionnaire. Some intestinal microorganisms, such as Bifidobacterium, Faecalibacterium , Bacteroides group or Clostridium XIVa, decreased with age up to 66-80 years of age. Interestingly, the levels of some of these microorganisms were recovered in the very old age group (> 80 yo) whom, in addition, presented significantly higher levels of Akkermansia and Lactobacillus-group. Correlation analyses showed a positive association of Akkermansia and lactobacilli with age and a negative one for Faecalibacterium. In general, ageing was related with a reduction in SCFA levels and the relative proportion of acetate. Dietary intakes of major food groups were also found to be different among age-groups. Given the potential role that alterations on the IM may have in terms of impairing homeostasis and resilience, it is of importance to understand the ageing process also from the IM perspective. This would allow designing nutritional interventions for promoting a healthy ageing.